An imaging apparatus including, for example, a CMOS (Complementary Metal Oxide Semiconductor) image sensor is applied to a digital camera or the like. In such an imaging apparatus, there are formed a pixel region in which a photodiode for converting incident light into a charge is arranged, and a peripheral region in which peripheral circuits for processing or otherwise handling the charge converted by the photodiode as an electrical signal are arranged. In the pixel region, the charge generated in the photodiode is transferred by a transfer transistor to a floating diffusion region. The transferred charge is converted by an amplification transistor into an electrical signal, is output as an image signal, and the output image signal is processed in the peripheral region.
In the pixel region and the peripheral region, a semiconductor device such as a photodiode or a field effect transistor is formed in a device formation region defined by a device isolation region. In recent years, so-called trench isolation (STI: Shallow Trench Isolation) is adopted for a device isolation region, in order to accommodate miniaturization of imaging apparatuses.